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<H2>exception</H2>
<P><B>Module:</B>&nbsp;&nbsp;Standard C++ Library&nbsp;&nbsp;&nbsp;<B>Library:</B>&nbsp;&nbsp;<A HREF="2-2.html">Language support</A></P>

<PRE><HR><B><I>Does not inherit</I></B><HR></PRE>

<UL>
<LI><A HREF="#sec1">Local Index</A></LI>
<LI><A HREF="#sec2">Summary</A></LI>
<LI><A HREF="#sec3">Synopsis</A></LI>
<LI><A HREF="#sec4">Interface</A></LI>
<LI><A HREF="#sec5">Example</A></LI>
<LI><A HREF="#sec6">Constructors</A></LI>
<LI><A HREF="#sec7">Destructor</A></LI>
<LI><A HREF="#sec8">Public Member Operator</A></LI>
<LI><A HREF="#sec9">Public Member Function</A></LI>
<LI><A HREF="#sec10">See Also</A></LI>
<LI><A HREF="#sec11">Standards Conformance</A></LI>
</UL>
<A NAME="sec1"><H3>Local Index</H3></A>
<H4>Members</H4>
<UL><TABLE CELLPADDING=3>
<TR><TD VALIGN=top>
<A HREF="#idx628">exception()</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx631">operator=()</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx632">what()</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx630">~exception()</A><BR>
</TD></TR>
</TABLE></UL>

<A NAME="sec2"><H3>Summary</H3></A>
<P>Class <B><I>exception</I></B> is the base class that supports logic and runtime errors.</P>
<A NAME="sec3"><H3>Synopsis</H3></A>

<PRE>#include &lt;exception&gt;

namespace std {
  class exception;
}
</PRE>
<A NAME="sec4"><H3>Interface</H3></A>

<UL><PRE>namespace std {
      class exception {
      public:
        exception() throw();
        exception(const exception&amp;) throw();
        exception&amp; operator=(const exception&amp;) throw();
        virtual ~exception() throw();
        virtual const char* what() const throw();
      };
}
</PRE></UL>
<A NAME="sec5"><H3>Example</H3></A>

<UL><PRE>//
// except.cpp
//

#include &lt;iostream&gt;
#include &lt;stdexcept&gt;


#ifndef _RWSTD_NO_EXCEPTIONS

int main ()
{
   try {
       // Enable exceptions in cin.
       std::cin.exceptions(std::ios::eofbit);

       // Clear all bits and set eofbit.
       std::cin.clear(std::ios::eofbit);
   }
   catch (const std::ios::failure &amp;e) {
       std::cout &lt;&lt; "Caught an exception: " 
                 &lt;&lt; e.what () &lt;&lt; std::endl;
   }
   catch (const std::exception &amp;e) {
       std::cout &lt;&lt; "Caught an exception: " 
                 &lt;&lt; e.what () &lt;&lt; std::endl;

       return 1;   // Indicate failure.
   }
   catch (...) {
       std::cout &lt;&lt; "Caught an unknown exception" 
                 &lt;&lt; std::endl;

       return 1;   // Indicate failure.
   }

   return 0;
}

#else

int main ()
{
    std::cout &lt;&lt; "Exceptions not supported." &lt;&lt; std::endl;

    return 0;
}


#endif   // _RWSTD_NO_EXCEPTIONS

Program Output:

Caught an exception: std::cin: stream object has set ios::eofbit
</PRE></UL>
<UL><PRE></PRE></UL>
<A NAME="sec6"><H3>Constructors</H3></A>

<A NAME="idx628"></A><PRE><B>exception</B>() throw();</PRE>
<UL>
<P>Default constructor. Constructs an object of class <B><I>exception</I></B>.</P>
</UL>


<A NAME="idx629"></A><PRE><B>exception</B>(const exception&amp;) throw();</PRE>
<UL>
<P>Copy constructor. Copies an <B><I>exception</I></B> object.</P>
</UL>

<A NAME="sec7"><H3>Destructor</H3></A>

<A NAME="idx630"></A><PRE>virtual <B>~exception</B>() throw();</PRE>
<UL>
<P>Destructor. Destroys an object of class <B><I>exception</I></B>.</P>
</UL>

<A NAME="sec8"><H3>Public Member Operator</H3></A>

<A NAME="idx631"></A><PRE>exception&amp; 
<B>operator=</B>(const exception&amp;) throw();</PRE>
<UL>
<P>Assignment operator. Copies an <B><I>exception</I></B> object.</P>
</UL>

<A NAME="sec9"><H3>Public Member Function</H3></A>

<A NAME="idx632"></A><PRE>virtual const char* 
<B>what</B>() const throw();</PRE>
<UL>
<P>Returns an implementation-defined, null-terminated byte string representing a human-readable message describing the exception. The message may be a null-terminated multibyte string, suitable for conversion and display as a <B><I><A HREF="wstring.html">wstring</A></I></B>.</P>
</UL>

<A NAME="sec10"><H3>See Also</H3></A>
<P><A HREF="exceptions.html">Exceptions</A>, <B><I>bad_alloca</I></B>, <B><I><A HREF="bad-cast.html">bad_cast</A></I></B>, <B><I><A HREF="bad-exception.html">bad_exception</A></I></B>, <B><I><A HREF="bad-typeid.html">bad_typeid</A></I></B>, <B><I><A HREF="domain-error.html">domain_error</A></I></B>, <B><I><A HREF="invalid-argument.html">invalid_argument</A></I></B>, <B><I><A HREF="ios-base.html#failure">ios_base::failure</A></I></B>, <B><I><A HREF="length-error.html">length_error</A></I></B>, <B><I><A HREF="logic-error.html">logic_error</A></I></B>, <B><I><A HREF="out-of-range.html">out_of_range</A></I></B>, <B><I><A HREF="overflow-error.html">overflow_error</A></I></B>, <B><I><A HREF="range-error.html">range_error</A></I></B>, <B><I><A HREF="runtime-error.html">runtime_error</A></I></B>, <B><I><A HREF="underflow-error.html">underflow_error</A></I></B></P>
<A NAME="sec11"><H3>Standards Conformance</H3></A>
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 19.1</I></P>

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